Field of the Invention
The present disclosure generally relates to a device for mixing precise, predetermined proportions of powder, extracted from a storage source, with fluid to make a mixture. More specifically, and without limitation, the present disclosure relates to improving the aseptic transfer of lyophilized powder and reconstitution fluid into a metering device for medical used herein, the term reconstitution includes mixing a solid phase into a fluid phase resulting in a solution, a suspension, or a colloide.
Description of Related Prior Art
In the administration of medical treatment, patients often receive injections of reconstituted mixtures. A therapeutic mixture is the result of mixing powder, previously altered for preservation and storage, with liquid, thereby returning the powder to its approximate, original state. Drugs, for example, are often packed and stored in powder form in order to preserve their utility. By way of example, ampicillin, an antibiotic commonly used to treat bacterial infections, is commonly stored in powder form because, in liquid form, it has a short shelf life. For this reason, the administration of ampicillin requires dissolving a powder into liquid to form a solution.
Traditionally, to accomplish this mixing, a user—i.e., a health care provider or a patient—uses a syringe to withdraw a diluent (the mixing liquid) from a first container, and deliver the diluent into a second container where the powder is stored. Delivery of the diluent is accomplished by inserting the syringe into the second container. To ensure the diluent mixes completely with the powder, the syringe is ordinarily removed from the second container while the second container is manipulated or shaken to fully reconstitute the powder. Once the powder and diluent are fully incorporated into a solution, the user returns the syringe into the second container. The solution is then extracted from the second container, back into the syringe. Only then is the solution ready for injection into a patient. This cumbersome process suffers from several drawbacks.
For example, in preparing the mixture for injection into the patient, the syringe is the primary vehicle. Before the syringe is ready for injection, it is inserted into and removed from the first container. It is then inserted into and removed from the second container two times, once to inject the diluent and once to remove the mixture. With each step, the risk of contamination increases because the syringe can come into contact with non-sterile surfaces. Such unsanitary conditions could result in serious harm to the patient.
Further, because the traditional process involves introducing diluent into the powder container, the powder container can be used only once. As a result, multiple single-use containers are used to store powder, thereby increasing the complexity of storage and cost, as well as creating waste.
Yet further, the abovementioned process is unavoidable because prior art devices were incapable of drawing powder through the needle's narrow conduit, and into the syringe.
Even further, the abovementioned process suffers from the looping problem, which describes the problem of mixing different strength powders to achieve a specific, prescribed dosage. Traditionally, a powdered drug will have different formulations related to different strengths or potencies. This occurs because treatments differ between patients. Indeed, not each person using the same drug requires the same level of potency. A problem arises, however, when trying to generate a particular drug strength because of how the powder is stored. The potency of a drug is measured by international units (“IU”) and is a function of the amount used. A single drug can have several different IUs, each stored in different vials with identifying markings. If a prescription calls for a drug having a specific IU that does not match the IUs stored in the available vials, a user will have to mix powders from varying vials to achieve the prescribed drug. The problem is further complicated because different drug strengths are separated by predetermined intervals that may be inconsistent with the prescribed dosage. So, for example, if a prescription calls for a drug having 120 IU, and the drug is stored in two vials, one having 100 IU and the other having 50 IU, the precise dosage cannot be achieved. The user will therefore have to take a dosage with either a lower or higher potency than the one prescribed. This lessens the efficacy of the treatment.